Biosensors are devices for sensing and detecting bio-entities, and typically operate on the basis of electronic, chemical, optical, or mechanical detection principles. Detection can be performed by detecting the bio-entities themselves, or through interaction and reaction between specified reactants and the bio-entities. Biosensors are widely used in different life-science applications, ranging from environmental monitoring and basic life science research to Point-of-Care (PoC) in-vitro molecular diagnostics.